六线铁路钢桁梁斜拉桥桥面系共同作用研究

A Study On the Co-action between Floor system and Main trusss of Six line railways steel truss Girder Cable-stayed Bridge

新白沙沱长江大桥主桥为(81+162+432+162+81)m的五跨连续钢桁梁斜拉桥,大桥搭载六线铁路,其中上层通行四线客专,下层通行两线货线,是国内首座六线铁路桥。上层桥面采用整体桥面,下层桥面采用纵横梁+道砟槽板形式。轨道结构均采用有砟轨道形式,桥梁恒载、活载重量均非常重。重载作用下,桥面系结构共同作用效应明显,下层纵横梁桥面系受力极为关键。文章对纵横梁桥面系共同作用效应进行了研究,结果表明通过合理设置制动架和适当的施工处理措施,可以改善桥面系共同作用效应,减少桥面系结构受力,特别是横梁的面外弯矩。

The main bridge of the New Baishatuo Yangtze River Bridge is a five span continuous steel truss girder cable-stayed bridge with span arrangement(81+162+432+162+81)m.The bridge is designed to carry six line railways, the upper deck of the bridge is designed to carry four line passenger dedicated railways, while the lower deck to carry two line freight railways, and the bridge is the first railway bridge to carry six line railways in China.The orthotropic integral deck is adopted in the upper deck, and longitudinal-and-crossing beam system deck is used in the lower deck. Ballast track structure is adopted in both decks,so the bridge has to carry both heavy dead load and live load, under such a heavy load, the coaction between floor system and main truss is significantly, the mechanical performance of the longitudinal and crossing beam system deck becomes very important,The coaction between floor system and main truss is studied in this paper, the results indicated that the force of the longitudinal and crossing beam system especially the out-of-plane moment of the cross beam can be obviously reduced by reasonable setting of brake system and rational construction measures.